Asian Longhorned Beetle (ALB)

Anoplophora glabripennis

Not Present In Utah

Asian longhorned beetle (ALB) (Coleoptera: Cerambycidae) is an invasive wood-boring
pest that is a major threat to many hardwood tree species and to maple syrup production.
It was first detected in the U.S. in New York during the 1980s, and probably arrived
via wood packing material from China. The first major infestation of ALB in the U.S.
was in Brooklyn in 1996. Soon after, infestations were found in other eastern locations,
including Chicago and New England. ALB is currently only found in Massachusetts, New
York, and Ohio, and is considered to have been successfully eradicated from New Jersey
and Illinois. The western U.S. is thought to be less susceptible to ALB establishment,
given the lack of suitable host plants outside urban areas.

Description

Adults are large, conspicuous beetles that are bullet-shaped, 3/4 – 1 1/2 inches in length
(not including the very long black and white antennae), and have a glossy-smooth black
body with irregular white spots. Some adults, although generally rare, have yellow
spots and newly emerged adults may have a bluish tinge to their feet and antennae.
The scutellum, or the triangular segment between the top of the wing covers, is black
(a similar looking native insect has a white scutellum - see Images section).

Eggs are roughly the size of a grain of rice (about 1/4 inch in length). They are mostly
flat, creamy-white in color, and are laid individually in an aggregated pattern and
in craters (oviposition pits) chewed into the bark by the adult female. Eggs can be
found underneath the bark along main branches and the lower crown, but may also be
found on the lower trunk.

Larvae are typical of roundheaded beetle larvae. They are cylindrical, ribbed, and light
yellow or white. Larvae can reach up to 2 inches in length. Young larvae create galleries
just under the bark, but tunnel into the heartwood of the tree as they age.

Pupae are about 1 1/2 inches in length and about the same color as larvae, but have traits
that resemble the adult. Pupae darken in color as they develop.

Life History

ALB has one generation per year. Adults emerge from host trees in late spring and
can be found throughout the summer, up until about the first frost. Adults feed on
leaf veins and bark of young twigs for 10–20 days before mating. A female may lay
as many as 90 eggs in her lifetime.

Eggs hatch within a couple of weeks and the newly emerging larvae feed on the cambium
and sapwood, eventually tunneling deeper into the heartwood. ALB typically overwinters
as a larva.

The following spring, larvae begin to chew their way toward the outside of the tree,
where they pupate. Pupation lasts about 20 days, with adults emerging from trees during
the late spring. Adults may remain on the tree they developed in, or fly short distances
to infest new trees.

Plant Hosts

ALB infests more than 100 different tree species, making it especially threatening
to our forests and incredibly difficult to detect and eradicate. Maple is the preferred
host, but there are many other trees it will attack, such as ash, birch, elm, poplar,
willow, and sycamore. Some trees appear to not be at risk of ALB infestation, including
oak and honeylocust. It is unknown if ALB infests conifer species.

Damage Symptoms

Both adults and larvae feed on host trees, although the larvae cause the most damage.
Adults will feed on leaf veins, and the females chew craters (oviposition pits) into
tree bark, leaving mandibular (mouthpart) marks that can be seen around the edges
of the pit. Craters are about 1/2 inch in diameter and vary in shape from circular
to oval, depending on bark thickness. Freshly chewed pits are easier to see because
the inner bark contrasts more sharply with the outer bark. ALB adult exit holes are
perfectly round, nearly dime-sized (3/8 inch in diameter), and may ooze sap.

Larvae bore into and feed on the cambium and sapwood, creating large hollow chambers
that can be seen in cross-sections of the trunk. Deposits of frass (sawdust-like insect
waste) may collect at tree trunks and limb bases. Severe larval infestations lead
to dead branches and can make tree limbs more likely to break during storms and cause
damage to nearby structures. Larval feeding also disrupts the tree's ability to uptake
water and nutrients, causing it to slowly die. Infested trees may be associated with
drooping leaves and discolored foliage.

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Brown Marmorated Stink Bug (BMSB)

Halyomorpha halys

Present In Utah

Brown marmorated stink bug (BMSB) (Hemiptera: Pentatomidae) is a major pest of many
agricultural crops, including fruits, vegetables, and ornamentals. BMSB is also a
nuisance pest that will congregate and invade homes and other buildings during the
fall and winter.

Originally from Asia, BMSB was first found in the U.S. in Pennsylvania around 1996,
but was initially misidentified as a local species. In 2001, after increasing homeowner
complaints, BMSB was positively identified as a new invasive species. BMSB has since
expanded its range to more than forty states. Its current distribution can be found
at stopbmsb.org.

BMSB was first detected in Utah in 2012, and has been found in Cache, Weber, Davis,
Salt Lake, and Utah counties as of May 2016.

Identification

Adultsare shield-shaped, and about 5/8 inch long and 1/2 inch wide. The term “marmorated”
refers to the brown marbled pattern on the adult bodies. Their antennae, legs, and
posterior edge of the back have distinct light and dark banding patterns. BMSB “shoulders”
are rounded and smooth. Adults have undersides that are light gray or tan.

Eggsare barrel-shaped, 1/16 inch wide, and translucent to white in color. As eggs mature,
dark triangular-shaped spots become visible. Eggs are typically laid on the underside
of leaves and in masses of approximately 20-30 (average of 28).

Nymphsvary in color, depending on age. Newly hatched nymphs are tick-like in appearance,
have yellow-red backs with black stripes, and tend to huddle near the egg mass. As
nymphs mature, they disperse from the egg mass, darken in color, develop wing pads
(immature wings), and begin to look similar to adults in color and size. Nymphs range
from 1/10-1/2 of an inch.

Life History

BMSB appears to have only one generation per year in Utah, but multiple generations
are possible. Adults become active in the spring, and feed on any green, growing plant
for about two weeks before mating. A female may lay as many as 400 eggs in her lifetime.

In Northern Utah, BMSB egg masses have been detected from late May to late August.
In other states, eggs have been observed through September. Eggs hatch within a few
days and the development time for each nymphal stage is about 1 week between molts,
depending on temperature.

From October to November, adults (and sometimes nymphs) move to protected sites where
they mass together for the winter, including under the bark of standing trees, downed
and dead trees, and inside buildings, especially in attics and walls. Adult aggregations
may be seen on the outside of buildings, and in window seals, air vents, and cracks
and crevices in concrete or buildings.

Plant Hosts

BMSB is a tree-loving bug, and has a very broad plant host range. Adults and nymphs
will feed on vegetative and reproductive plant structures, including stems, leaves,
fruits, seeds, pods, buds, and flowers. Plants that bear fruiting bodies (e.g., fruits
and vegetables) are especially vulnerable to this pest.

BSMB prefers stone and pome fruits, berries, and recently has been found to feed on
citrus fruits. Vegetables are also highly susceptible to BMSB feeding, especially
solanaceous fruits (tomatoes and peppers), legumes, and sweet corn.

Damage Symptoms

BMSB, like all stink bugs, has a piercing-sucking mouthpart. Mouthparts are used to
puncture plant cells to obtain nutrients in the sap and inject salivary secretions
that help break down the plant tissue.

Common feeding damage symptoms include dimples, pits, and discoloration, softening
of fruits, “cat facing,” and the development of corklike tissue. Sometimes there will
be no visible external damage to the fruit, but will only be seen underneath the skin.

Although they can be a major agricultural and domestic nuisance, BMSB does not bite,
sting, spread mammalian diseases, or bore into or damage wooden structures. It is
not directly harmful to people, pets, or buildings.

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Emerald Ash Borer (EAB)

Agrilus planipennis

Not Present In Utah

Emerald ash borer (EAB) (Coleoptera: Buprestidae) is an invasive woodboring beetle
that has caused the decline and mortality of tens of millions of ash trees (Fraxinus
spp.) in the U.S. It is considered the most destructive forest pest to ever invade
North America.

Originally from Asia and parts of Russia, EAB was first discovered in the U.S. in
2002 in southeastern Michigan. It most likely arrived to the U.S. as larvae or pupae
embedded in ash pallets, crates, or packing material transported by airplanes or cargo
ships. EAB is now known to occur in 26 eastern and midwestern states, and is rapidly
expanding its range. It has not yet been found in Utah, but an infestation has been found in neighboring Boulder, Colorado.
Information on its most current distribution can be found at Emerald Ash Borer Information.

Identification

EAB undergoes complete metamorphosis, which includes four distinct stages: adult,
egg, larva, and pupa. The immature stage (larva) does not resemble the adult.

Adults are metallic green beetles with bronze heads, short saw-toothed antennae, flattened
backs, rounded bellies, and iridescent purple-red abdominal segments beneath their
wings. They are bullet-shaped, lack a defined waist, and are about 1/2 inch long and
1/8 inch wide.

Eggs are oval to round, 1/16 inch in diameter, cream-colored when first deposited, and
reddish-brown as they develop. Due to their small size, eggs are not easily observed.

Larvae are cream-colored with 10 body segments and a flattened abdomen. They can reach a
length of 1 inch when mature, are tapeworm-like in appearance, and have a pair of
brown, pincer-like appendages on the last abdominal segment. Their brown head is mostly
retracted, but the mouthparts are visible externally. The last instar larva (pre-pupa)
will excavate a tiny chamber and curve back on itself (J-shaped).

Pupae have the characteristic shape of the adult, with short saw-toothed antennae and a
blunt spine at the tip of the last abdominal segment. Newly developed pupae are white,
but then take on the adult coloration as they develop.

Life History

EAB has a one-year life cycle. Adults emerge from ash trees in the spring when degree-day
(DD) accumulations reach 450- 550 DD (using a base temperature of 50°F), which in
Utah can occur as early as mid-April in southern Utah or mid-May in northern Utah.
Peak emergence is at 900 to 1,100 DDs (mid-to-late July). For more information on
DDs in Utah, visit https://climate.usurf.usu.edu/traps/.

Adults live 3-6 weeks and will feed on ash leaves for 1-2 weeks before searching for
mates. Mated females will lay eggs on bark or in bark crevices. Females can lay 60-90
eggs over the course of their lifetime. Eggs are laid individually or in groups, and
hatch after 2-3 weeks.

After eggs hatch, the newly developed larvae bore into the tree, feeding on the phloem
and cambium layers, and eventually pass through four larval stages. EAB overwinters
as a full-grown larva or pre-pupa in a tiny chamber excavated in the sapwood. They
pupate in the spring and repeat the life cycle.

Plant Hosts

EAB attacks all North American ash (Fraxinus) species. They attack small, large, stressed,
and even healthy ash trees.

EAB was previously thought to specialize on ash, but was recently found infesting
white fringe trees (Chionanthus virginicus) in Ohio and Illinois. This may indicate
that EAB has a wider host range than originally thought or that it is adapting to
utilize new hosts. Both ash and fringe trees are members of the olive family.

Utah has two native ash species that are susceptible to EAB - the small, shrubby singleleaf
ash, Fraxinus anomala, that occurs sporadically in southern Utah and velvet ash, Fraxinus
velutina, in SW canyons. Yet, various planted ash species make up a substantial component
of our urban forests. Ash comprises up to 30% of the urban canopy in many Utah communities,
and all are susceptible to EAB attack.

Damage Symptoms

Larvae are the primary damaging life stage and are responsible for killing trees.
They chew through bark into the phloem and sapwood, creating serpentine-shaped and
excrement filled galleries, which disrupt the flow of nutrients and water, starving
the tree. Larval galleries curve at near right angles so that the tunnel length, as
measured in a straight line from start to end point, is less than half of the actual
total tunnel distance (note: any serpentine gallery in an ash tree should be suspect).
Galleries are more common in the upper canopy in newly infested trees and increase
in size as larvae feed and grow. Galleries, however, can be found lower on the trunk
as the infestation progresses.

Larval infestations can also lead to bark splits, canopy dieback, epicormic branching
(suckers) at the base of large, dead branches or the base of the tree, and increased
woodpecker activity. Woodpeckers and other bark foraging birds feed on up to 85% of
the EAB in an infested tree.

When EAB densities are high, small trees can die within 1-2 years of becoming infested,
whereas large trees are killed within 3-4 years. Unfortunately, EAB infestations are
difficult to detect, especially during the early stages of invasion, and are nearly
always fatal to the tree unless insecticides are used to protect trees.

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Gypsy Moth (GM)

Lymantria dispar

Not Present In Utah

Gypsy moth (GM) (Lepidoptera: Erebidae) is an invasive defoliating pest that is a
serious threat to U.S. forests. There are two related subspecies of concern to the
U.S., the European GM (Lymantria dispar dispar) and the Asian GM (L. dispar asiatica).
The two subspecies can only be distinguished from each other by DNA tests. Both pose
a threat to U.S. forests, however, although the Asian GM poses a greater threat than
the European GM because it has a broader host range than the European GM, and the
females can fly 20-25 miles per day (European GM females do not fly).

The European GM was first brought to the U.S. in 1869 to start a silkworm industry.
It is now well-established in the eastern U.S., and has been detected in many other
parts of the country, including Utah. Populations of European GM have been found and
successfully eradicated twice in Utah (1988 and 2008).

The Asian GM was first detected in the U.S. in 1991, and likely arrived on ships infested
with egg masses traveling from Russia. In recent years, there have been several introductions
of Asian GM to the U.S., including Washington, Oregon, Georgia, and South Carolina
in 2015. The Asian GM has not been detected in Utah.

Identification

Adult males are grayish-brown moths with feathery antennae and a wingspan of about 1 1/2
inches. Adult females have creamy white wings with black wavy markings, thread-like
antennae, and a wingspan of about 2 1/2 inches. Both males and females have an inverted
V-shape that points to a dot on the wings.

Eggs occur in conspicuous, velvety masses that are 1-2 inches long, tan in color, and
firm to the touch. The eggs inside are black and pellet-like. Egg masses may contain
between 100-1,000 individual eggs, and can be found on many outdoor surfaces, including
trees, houses, patio furniture, and vehicles.

Larvae go through 5-6 growth stages. Young larvae are small (1/8 inch long), black caterpillars
with long, black hairs on the body, and may have irregularly shaped yellow marks visible
on the upper body surface. Older larvae are more easily identifiable. They have long,
tan bristles, five pairs of blue spots followed by six pairs of red spots lining the
back, and yellow spots along the sides of the body. Mature larvae can reach 2 1/2
inches in length. GM larvae do not produce silken tents or have extensive webbing.

Pupae are teardrop shaped, about 2 inches long, dark brown, and have hardened shells covered
in small hairs. They can be found in bark crevices or other cryptic locations.

Life History

GM has one generation per year. Adults emerge from pupal cases anywhere between late
June and early August, with peak emergence in mid-July. Females will remain on the
tree and release pheromones to attract mates. Egg masses are deposited by females
in July or August and are found on trees and other outdoor substrates. The eggs are
the overwintering stage, and will hatch the following spring (April through early
May). Young larvae climb to the tops of trees, where they feed and dangle from silk
strands until they are dispersed by wind. Young larvae feed during the day in the
upper canopy, whereas mature larvae feed at night but move to the base of trees or
bark crevices to hide during the day. Pupation takes place between July and August.

GM populations go through cycles in which the populations increase for several years,
then decline, and then increase again. GM outbreaks can take place for up to 10 years.

Plant Hosts

Larvae feed on the foliage of hundreds of tree species. The most preferred hosts include
oak, aspen, apple, birch, and poplar, but they will also infest walnut, cherry, elm,
hickory, honey locust, maple, and several western conifers. Asian GM larvae tend to
feed on evergreen and deciduous trees, whereas European GM larvae feed primarily on
deciduous trees. Least preferred hosts include ash, dogwood, and lilac, but some research
suggests that GM may be able to adapt to unsuitable host plants.

Damage Symptoms

Larvae are the damaging life stage. They defoliate trees, leaving trees weakened,
more susceptible to drought, diseases and other pests, and can eventually kill trees
and entire forests. GM larvae lower property values in infested urban areas, and their
debris (frass or insect excrement, egg masses, and pupal casings) can be a nuisance
to homeowners. Healthy trees can usually tolerate 1-2 years of GM attack; however,
repeated infestations will weaken the tree to a point to which it cannot recover.

Images

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Japanese Beetle (JB)

Popillia japonica

Not Present In Utah

Japanese beetle (JB) (Coleoptera: Scarabaeidae) is an invasive insect that has an
extensive plant host range. Plant damage is inflicted by both adult and immature life
stages. Adult JB feeds on the foliage of many plant species, while the immature stage,
larva (white grub), primarily feeds on the roots of turf grasses.

JB was first found in the U.S. in 1916 in a New Jersey nursery. It was likely introduced
from Japan in shipments of ornamental plants. Since the 1970s, JB has been found throughout
many western states, including Utah in 2006. An eradication program directed by the
Utah Department of Agriculture and Food was successful in eliminating JB from Utah.
Recent monitoring traps have detected extremely low adult activity (e.g., in 2015,
two beetles were found in Salt Lake City).

Identification

Adults are about 1/4 inch wide and 1/2 inch long, oval shaped, and have a metallic green
head and mid-section with copper-brown wing covers. They have five pairs of white
hair tufts along the sides of the abdomen and another pair on the last abdominal segment.
Their legs have prominent spines and the underside of their body is metallic green
and copper-brown.

Eggs are about 1/16 inch in diameter, cylindrical when first deposited, but nearly round
and 1/8 inch in diameter when mature.

Larvae, or "white grubs," are creamy white with a grayish-brown hind end. They have a yellow-brown
head with dark mandibles, and range in size from 1/8 inch in length upon hatching
to 1 inch at maturity. Larvae have three pairs of underdeveloped legs and long brown
hairs dispersed with short, blunt spines on the body. Larvae form a "C" shape when
at rest. Many scarab beetle larvae, such as May/June beetles and chafers, look just
like JB larvae. Suspect larvae should be submitted to the UPPDL for screening.

Life History

JB has one generation per year. Most of the JB life cycle is spent underground, only
emerging as adults to feed, mate, and lay eggs during the summer.

Adults emerge from pupae in the soil during June and July, and feed on a wide range
of crop, garden, and ornamental plants over a 6-8 week period. Mated females will
fly to turf grass and burrow 2-3 inches underneath the soil to lay eggs. Each female
can lay up to 60 individual eggs.

Larvae feed on plant roots in the spring, summer, and fall. Most larvae overwinter
as 3rd instars and burrow at a soil depth of 2-6 inches to spend the winter. The following
spring, they continue to feed, then pupate and emerge as adults. Pupation takes place
in an earthen cell made by the final larval instar.

JB larvae prefer fescues, perennial ryegrasses, Kentucky bluegrass, and bentgrass.
The larvae also feed upon roots of young ornamental trees and shrubs, and garden crops
such as corn, peas, beans, tomato, and onion.

Damage Symptoms

Adults chew on the leaves, flowers, fruit, and in some cases, stems of plants. They
are voracious feeders. Adults skeletonize leaves, chewing away softer tissue, and
leaving the veins. They also chew holes in flower buds and petals, soft fruits, and
corn silks. The adult beetles congregate and can destroy crops in just a few days
before moving on. They also wreak havoc on ornamental plants.

The larvae attack plants below ground and feed on the roots of grasses and some trees,
shrubs, and vegetables. Large plantings of turf grasses (e.g., lawns and athletic
fields) are especially attractive as egg-laying sites.

While damage to grasses is initially difficult to detect, it becomes apparent during
late summer and early fall when grubs are large. The compromised grass roots are inefficient
in uptake of water and nutrients, and eventually turn leaves and stems yellow and
brown. Severely injured turf will die. Feeding damage appears as patches of dead and
dying plants mixed with healthy, unaffected grass. Turf with damaged roots is easily
pulled back from the soil surface to reveal the grubs underneath. The damaged turf
will also feel spongy and soft under-foot.

Images

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Spotted Wing Drosophila (SWD)

Drosophila suzukii

Present In Utah

The spotted wing drosophila (SWD), (Diptera: Drosophilidae), is an invasive vinegar
fly native to Japan and parts of Thailand, India, China, Korea, Myanmar, and Russia.
SWD was first detected in the U.S. in California in 2008. In Utah, it was first discovered
in a raspberry and blackberry field in Kaysville (Davis County). It is currently an
economic pest of soft fruits and vegetables throughout much of the U.S. SWD is named
for a dark spot on each wing of the male fly.

Other species of vinegar flies only attack fruit that is overripe or rotten, but SWD
females lay eggs in unripe, ripe, and overripe fruit. Because it will lay eggs in
fruit still maturing on the plant, larvae can be present in fruit that is harvested
for market. The larva is the main damaging life stage; the female fly punctures fruit
when laying eggs which can introduce secondary pathogen infections.

Identification

Adultsare about 0.1 in long with a pale brown body that has unbroken bands on the backside
of the abdomen, red eyes, and feather-like antennae. Males have a single black spot
on the edge of each wing and two dark bands (“sex combs”) on each foreleg. Females
can be distinguished from similar flies by their large, saw-like ovipositor (egg-laying
device) located on the back of their body. A hand lens or dissecting microscope is
helpful for identifying specimens.

Eggs are about 0.02 in long and 0.007 in wide, white to creamy translucent, cylindrical
in shape, with two respiratory filaments on one end (filaments may protrude from fruit
with eggs).

Larvae are small (<0.01 in long), cream-colored maggots with black mouthparts and are tapered
at both ends of their body.

Pupae are about 0.1 in long, brown, cylindrical capsules that have two extensions on one
end.

Life History

SWD may complete an estimated 3-16 generations per year in Utah. Adults increase activity
in the spring (emerging around mid to late April in Utah), however, low populations
are difficult to detect and few SWD adults have been detected before August. In locations
outside of Utah with higher SWD populations, adult emergence peaks in June and July
(sweet cherry harvest) and again in September (grape harvest).

Egg-laying begins in the spring when average temperatures exceed 50°F (10°C), and
continues until average temperatures decline below 42°F (5.5°C) in the autumn. Females
typically lay 1-3 eggs per fruit and 7-16 eggs per day. A female may lay over 350
eggs in her lifetime. Eggs typically hatch quickly, in 12-72 hours. Larvae feed inside
the fruit for 3-12 days before pupating. Larvae can pupate within or on the outside
of fruit, or they may drop to the soil. Pupae are usually found in fruit, or in the
leaf litter or soil below infested fruit. Pupation requires from 3-15 days.

Eggs and larvae have not been detected in Utah due to very low populations; however,
because adults have been detected in the same locations in subsequent years, this
suggests that SWD is reproducing and completing full generations in Utah. In Utah,
trap captures of adults peak from late September to November. The adult lifespan can
vary from 8 days to 9 weeks depending on environmental conditions and time of year.
Both male and female adults can overwinter. When average minimum temperatures in the
fall drop to 41°F (5°C), SWD adults seek protected sites for the winter, such as under
leaf litter and rocks.

Plant Hosts

SWD hosts include tree fruits, berries, some soft-skinned vegetable fruits, and many
ornamental and wild fruits. SWD prefer fruits with soft skin; favorites include cherry,
peach, blueberry, raspberry, blackberry, and grape. Firmer-skinned fruits, such as
apple, tomato, and grape, become more attractive to SWD when they are over-ripe or
damaged.

Fruits are most vulnerable to attack by SWD as they near maturity. On tough-skinned
fruits, female SWD will glue eggs to the surface with a sticky excretion. Although
damaged, spoiled or fermented fruit attracts adults, egg-laying is low in damaged
fruit and almost no egg-laying occurs in spoiled fruit.

With the potential for numerous generations each year, infestation levels of SWD can
quickly increase to concerning levels. Fruits that are particularly at high risk for
infestation include unharvested pollinizer, organic, wild, and ornamental fruits.
Because SWD is a late season pest, fruits that are harvested early in the season may
be less susceptible to SWD infestations.

Damage Symptoms

Females cause injury to fruit via oviposition. Egg-laying scars are typically pin-prick
holes in the fruit skin. Primary damage is caused by larval feeding and tunneling
in the fruit flesh. Oviposition and larval damage cause soft tissue in the fruit and
an increased chance of mold, wrinkling, and decay.

The area of oviposition or pin-pricks may become sunken and when closely examined,
eggs within fruit may have two hair-like filaments protruding through the fruit skin.
Fruit that has been infested may also exude a sappy juice when squeezed.

After 5-7 days of larval feeding, the fruit skin begins to show damage symptoms. Larval
feeding will cause the fruit to become soft, wrinkled, and spotted which may lead
to fruit decay. As the larvae increase in size, they cut breathing holes through the
skin of the fruit. Several methods to monitor fruit for infestation by SWD are discussed
in the monitoring section.

Images

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Velvet Longhorned Beetle (VLB)

Trichoferus campestris

Present In Utah

The velvet longhorned beetle (VLB) (Coleoptera: Cerambycinae) is a wood-boring beetle
native to Asia and Russia. It was first detected in North America in 2002 in Quebec,
Canada, and in Rhode Island, U.S. in 2006. In Utah, VLB was first found in South Salt
Lake City in July 2010. Detection traps in orchards, ornamental landscapes, and along
natural waterways indicate that VLB is widespread in Salt Lake and Utah counties.
VLB travels to new areas by infesting wood that is used as packing material for imported
commodities such as machinery, building supplies, glass, tools, and tiles.

In its native range, VLB prefers apple, mulberry, and hardwood and conifer timber
hosts. In Utah, larvae, pupae, and adult life stages of VLB have been found in peach
and cherry trees. It attacks healthy, stressed, and dead and dying trees. Due to its
polyphagous (feeds on many different hosts) life style, VLB poses a threat to Utah’s
orchard, landscape, and riparian wood lands.

Identification

Adults are about ½-3/4 inch long, with an elongated brown to orange colored body, and long
parallel wing covers. The name “velvet” comes from the fine hairs irregularly distributed
along the adult wing covers and body. These fine hairs can form light colored “spots”
along the body. Their legs and antennae are usually lighter in color than the body
and the segmented antennae are about ¾ the length of the body. Adults fly at night
and are attracted to lights.

Eggs are about 1/16 inch long and 0.02 inch wide and white to oval in shape.

Larvae are about ½ to 1 inch long and are yellow to white in color with a brown head, segmented
body, and short, poorly developed legs.

Pupae are about 3/4 inch long and 1/4 inch wide, with a white to cream colored body, and
long antennae that curve and are held close to the body.

Life History

VLB larvae complete their development in two or more years, overwintering in cells
they form beneath the bark; pupation occurs in the late winter to spring with a final
molt to the adult stage in spring to summer.

Adults chew round exit holes in tree bark to emerge from the end of May to mid-July;
peak flight and mating occurs from June to early August. Females lay their eggs on
the trunks and large branches of healthy, stressed, dying, and cut trees.

Larvae hatch and burrow into the tree bark forming galleries (tunnels) in the cambium
(conductive tissues) between the bark and sapwood. Older larvae tunnel into the sapwood
below the cambium and may move into the heartwood, increasing in size as they mature.
Larvae can tolerate dry wood; thus, their ability to bore into cut and dried wood.
Larval galleries range in size from 2 to 6 in (5 to 15 cm) wide.

Host Plants

In its native range, VLB prefers apple, mulberry, and a number of hardwood and conifer
timber tree species. Live tree hosts in Utah potentially include many cultivated and
wild species. Many tree species may also serve as dry wood hosts for VLB.

It is unknown whether VLB prefers stressed or healthy trees, however, it does seem
to be more attracted to medium to large sized trees. VLB has been found reproducing
in sweet cherry and peach trees in Utah, but not in apple yet. Nursery trees in the
U.S. are susceptible hosts to VLB larvae and may act as a reservoir for the pest to
spread to new areas.

Damage Symptoms

Tree injury symptoms include a thinning, wilted or yellowing canopy; round exit holes
on the trunk and main branches; frass (insect excrement) deposits at the base of the
tree; peeling bark; tunnels made by large larvae; and epicormic shoots (shoots that
grow from dormant buds beneath the bark, trunk, stem, or branch of a plant). Fruit
yield, tree longevity, and wood marketability can all be negatively impacted by a
VLB infestation.